I had an '03 v6 auto sr5 for 6 years.
Last of the jap built lux's - the quality is there. They get through about 16 l/100 as an average with the auto.
Put bigger tyres on and you'll start eating idlers and pitmans on corrugations - but that goes for any ifs ute.
Mine was body lifted, suspension lifted, locked front and ran 33's - it wasn't bashed around as a park toy, but was a very well used tourer which it did well.
They HATE deep water - always use a water blind if the water is any more than wheel height. I put the fan into the radiator on two occasions (both driver error), and being an auto the radiators are about $1200 each. If you havent got a blind just occy strap the fan to the chassis. Again, this could be said for most utes.
The 5vzfe has been around long enough to be proven as a reliable motor. They need oil changes to be on time (who doesn't?), and that's about it.
Mine was recalled for a transfer case replacement at the end of '04 - something about a porous casting - so if the transfer lookes newer that'd be why.
If yours is an sr5 I'd highly recommend getting a set of front hubs (about $250 from sunshine 4x4) and retrofit them. This saves wearing out cv boots which are a pain to replace, and also gives marginally better economy.
Hope this helps.
edit> toyota don't open the auto box's to service them so take it to an auto specialist for a service - Mine had 200 000 in it when I sold it and hadn't given any trouble.